In the field of logistics, that is the field of movement and supply of produce and materials, in particular in the transport of intermediate and finished products, containers have been developed which safely protect from physical damage a wide variety of product. Food and pharmaceutical products not only need protection from physical shock and pressures but also require temperature stability during transportation; otherwise goods can be damaged and be unusable, whether such damage is apparent or not.
For example, in the pharmaceutical industry, product often needs to be maintained within a temperature range: product may be packed in relatively small containers, which containers are relatively fragile—accordingly insulation must provide both physical and thermal stability. Equally, in the food industry, fish suppliers will often have chilled fish boxes which are designed to accept, say 20 Kg of product. The fish must be maintained at low temperatures, yet will be placed in containers which require a high degree of strength to prevent spillage.
As the standards of living increases, in developed markets, for example in Europe and North America, tropical foods—that is foods grown in far-away tropical places—are increasingly being stocked by supermarkets, delicatessens and the like. Short pick to distribution centre times in the producing country are matched by air carriers taking goods to the countries of consumption in similar lengths of time, whereby it is not uncommon for fruit to be on the plates of householders within two to three days of having been picked in a far-away country.
However, air transport poses a particular problem: Goods can be transported in tropical heat, packaged and placed upon pallets and the like containers whereby they are presented in aircraft style containers. Such goods may be left on runways at extreme temperatures (+40° C.) and then placed within a hold where low pressures and low temperatures exist during flight. At a destination airport the temperatures may well be sub-zero. A corollary to this is the production of temperature sensitive pharmaceuticals in a “developed” country which pharmaceuticals must be transported to another side of the world with similar temperature variations.
Both the above scenarios place transport managers in difficult positions. For air haulage, containers should weigh little, make use of non-rectangular hold spaces within aircraft; for the goods, they must be protected from shock, be maintained within a narrow temperature range, sometimes being equipped with temperature data loggers whereby a record of temperature within a container may determine whether or not a pharmaceutical is destroyed prior to use because of poor temperature handling. Refrigeration units may be provided with a container whereby temperatures maybe maintained, but then a source of electrical power or fuel for a powered generator is required.
To simplify transport with respect to airports, planes and handling equipment, there have been developed aircraft Unit Load Devices (ULDs) which comprise any type of pallet or container that can easily be loaded to the aircraft by a ground handler. Aircraft ULDs are units which interface directly with an aircraft loading and restraint system, without the use of supplementary equipment. There are pre-defined ULDs, such as LD3, LD7, which correspond to standard configurations and can be utilised on certain types of aircraft. There are still further ULDs that are shaped such that they have a rectangular base yet are not generally cylindrical, that is to say they extend outwardly, beyond the sides of the base, as they extend upwardly from the base. There is also an increasing demand for many containers, especially aircraft ULDs that they are transported from a supplier in a flat-pack fashion and they are constructed prior to use. This enables warehousing requirements to be reduced by typically 66-75%.
EP1025405 provides a container which has its cavity bounded by boundary elements, comprising a roof element, floor element, side walls and an end element. The boundary elements contain wall cores of hard foam plastics such as polyurethane. The rail core is edged with edging beams of fibre-reinforced plastics. The boundary elements are fixed rigidly to each other on connecting surfaces in the region of the edge beams. Standard doors can be used. Glass-fibre-reinforced plastics panels are combined with steel components to provide an assembly which whilst strong is not capable of being dismantled.
U.S. Pat. No. 4,266,670 provides a collapsible, reinforced, four sided container attached to a rigid base, of the type for transporting heavy products, such as iron. This design is collapsible whereby on a return journey it may be shipped in reduced size for reuse. This container is manufactured from reinforced corrugated cardboard. An example of this teaching is shown in FIG. 1, which container 10 comprises a pallet base 40, upon which are placed side panels 10-13. Each of the side panels have complementary edges having mortise and tenon elements, with an aperture running through, whereby stakes 107-110 may be inserted to enable the sides to remain upright. The panels provide a limited amount of temperature insulation, especially taking into account the relatively large size of the cardboard panels, being approximately 15 cm thick. One side may be easily opened for loading or unloading.
U.S. Pat. No. 2,556,418 provides a thermally insulated container and pallet. Telescopic tubes are mounted upon each of the four corners of a pallet to provide an enclosure frame which is built up with canvas straps and subsequently insulated. Refrigerant gasses may be introduced into the enclosure once a canvas wrap is positioned around the container.
GB1382230 provides a heat-insulating protective cover for temperature-sensitive goods comprises a carrier frame adapted to be positioned over the top surface of the goods, which rest on a pallet, and provided with support legs for this purpose. Walls of flexible heat-insulating material extend around the carrier frame and can be lowered from a retracted position to a lowered position, the walls being connected at their upper edges to a layer of heat-insulating material. Lift ropes are attached to the lower edges of the walls and extend up through eyelets to a common pull rope so as to permit the simultaneous lifting of all the walls to an upper position adjacent the carrier frame. The lower edges of the walls are provided with rings adapted to be hooked on to co-operating hooks on the pallet to provide a heat insulating space between the pallet and the carrier frame.
U.S. Pat. No. 3,955,700 teaches of an aircraft container which has a moulded reinforced fibreglass enclosure, which has two removable panels on one side which provide access to the interior. Whilst this solution provides a strong and rigid—yet resilient—container, when empty the container takes as much space as when full, which is not acceptable for many supply industries. Furthermore, by providing an enclosure, limitations are placed with respect to the order of packing and the addition of goods to be despatched, which can provide complications and expense to any freight manager.
It is notable that there are few thermally insulating cargo containers; either they are rigid yet not collapsible or are collapsible yet easily damaged when shifted by fork-lifts and other and/or are complex to assemble.